Nope, no load resistor required. It behaved pretty weirdly until I got it attached to the sigma22 but once it had that load it was happy and so far has worked without a hitch. It's a pretty elaborate way of doing things but once completed is really sweet. Next time I'll have a go at the thermal shut down feature.
And Al, yes I'm really serious. The entire amp was designed to be able to be deconstructed with a minimum of fuss so it won't really be that much work but I'm sick of things falling apart when I ship them so I'm going to go a bit berserk on this one. Some components already use other means of holding them permanently (lock washers, lock nuts etc) so that eliminates a few things too. Also, I'm going to have to do one serious tweak to the R channel which refuses to zero out the dc offset despite using what were supposed to be fully matched components.